Advanced Applications of Silk-Based Hydrogels for Tissue Engineering: A Short Review

Silk has been consistently popular throughout human history due to its enigmatic properties. Today, it continues to be widely utilized as a polymer, having first been introduced to the textile industry. Furthermore, the health sector has also integrated silk. The Bombyx mori silk fibroin (SF) holds the record for being the most sustainable, functional, biocompatible, and easily produced type among all available SF sources. SF is a biopolymer approved by the FDA due to its high biocompatibility. It is versatile and can be used in various fields, as it is non-toxic and has no allergenic effects. Additionally, it enhances cell adhesion, adaptation, and proliferation. The use of SF has increased due to the rapid advancement in tissue engineering. This review comprises an introduction to SF and an assessment of the relevant literature using various methods and techniques to enhance the tissue engineering of SF-based hydrogels. Consequently, the function of SF in skin tissue engineering, wound repair, bone tissue engineering, cartilage tissue engineering, and drug delivery systems is therefore analysed. The potential future applications of this functional biopolymer for biomedical engineering are also explored.

Can exposure to manganese and extremely low frequency magnetic fields affect some important elements in the rat teeth?

BACKGROUND

Length and level of exposure to electromagnetic fields (EMFs) is increasing in association with the widespread use of electrical and electronic devices and technological progress. The undesirable effects of extremely low frequency magnetic fields (ELF-MFs) on health have attracted considerable interest.

MATERIALS AND METHODS

Sixty-four four-month-old male Wistar rats divided into eight groups of eight rats each were used. Seven groups were exposed to varying dosages of manganese (Mn) and a 50 Hz magnetic field (MF) of approximately 1 mT, while the last group was set aside as the cage control group and not subjected to any procedure. This study was intended to investigate the interactions between the application of MF and Mn and the elements Ca, Zn, Mg, and P thought to be involved in caries, in rat teeth.

RESULTS

Levels of Ca, Mg, Zn, and P in the experimental group rats were different to those in the control group.

CONCLUSIONS

The results demonstrate that ELF-MF and Mn can have significant effects on levels of elements in rat teeth. Further experimental and epidemiological studies of ELF-MF and Mn are needed in order to evaluate their dental effects.

Whole-body microwave exposure emitted by cellular phones and testicular function of rats

This study investigated whether there are adverse effects due to microwave exposure emitted by cellular phones in male rats. Eighteen Wistar Albino rats were separated into three groups, a sham group and two experimental groups. The rats were confined in Plexiglas cages and cellular phones were placed 0.5 cm under the cages. In the first experimental group, cellular phones were in standby position for 2 h. In the second experimental group, phones were turned to the speech position three times each for 1 min duration over 2 h. Rats in the first and second experimental groups were exposed to microwaves emitted by phones for 2 h/day for a duration of 1 month. After the last exposure the rats were killed. Brain, eyes, ears, liver, heart, lungs, stomach, kidneys, testes, small and large intestines and skin of the rats were observed histologically. The decrease of epididymal sperm counts in the speech groups were not found to be significant (P > 0.05). Differences in terms of normal and abnormal sperm forms were not observed (P > 0.05). Histological changes were especially observed in the testes of rats of the speech groups. Seminiferous tubular diameter of rat testes in the standby and speech groups was found to be lower than the sham group (P < 0.05). Rectal temperatures of rats in the speech group were found to be higher than the sham and standby groups (P < 0.05). The rectal temperatures of rats before and after exposure were also found to be significantly higher in the speech group (P < 0.05). Specific absorption rate (SAR) was determined as 0.141 W/kg.

Effect of microwaves on survival of some bacterial strains

While the inhibitory effect of microwave radiation on microorganisms is being researched intensively, how microwave radiation brings about this effect has been a matter of discussion. Some researchers support that this effect is of a thermal character, whereas some others maintain a non-thermal effect. In this work, 1 ml suspensions of Pseudomonas aeruginosa, Pseudomonas acidovorans staphylococcus aureus and Staphylococcus epidermidis bacteria were subjected to microwave radiation at 2450 MHz and 550 Watts for periods of 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 25 and 30 seconds. When each result was compared with the CFU/ml results obtained from unradiated control group bacterial suspensions derived from stock cultures, significant conclusions were attained (P < 0.001). The same experiments were repeated with the application of conventional heating. The difference between the CFU/ml values of similar bacterial suspensions subjected to microwave radiation and conventional heating was significant (P < 0.001). Concurrently, the fact that the effect was exacerbated upon increasing of liquid volume during the application of microwave radiation was established via the results obtained through the application of microwave radiation to 1 ml and 5 ml bacterial suspensions (P < 0.001).